Substances such as polymeric agents are commonly bonded to inorganic material substrates, for instance, glass beads, to facilitate the chemical or physical interaction of the substance with one or more extraneous species to which the substance is subsequently exposed. Presentation of the substance on the substrate increases the amount exposed for interaction, and confers mechanical strength and other properties desirable for typical reaction conditions.
However, a number of substances, prominently including polymeric agents such as various carboxylated materials, cannot conveniently be bonded to an inorganic material substrate via a direct, chemical link which is hydrophobic. Thus, when deposited on the substrate, these substances are not sufficiently resistant to the solubilizing action of an aqueous medium that the substance remains on the substrate when in contact with the aqueous medium. Although hydrophobic bonding to the inorganic material substrate is possible in theory, it is impractical and extraordinarily expensive because such a process generally involves placing a monomeric material on the substrate, polymerizing the monomeric material and then subjecting same to a harsh sulfonation.
In a recent development, a polymeric agent of the type discussed above is held on an inorganic material substrate via a binding substance which forms a film or coating on the substrate. The binding substance may overlie or be intermixed with the polymeric agent on the substrate, so that when the binding substance is hardened it traps the polymeric agent, securing it on the substrate. Alternatively, the binding substance may be deposited on the substrate, with the polymeric agent overlying such substance, such that the binding substance anchors the polymeric agent by chemical bonding therebetween or by some other holding mechanism. The binding substance may itself bond to the inorganic material substrate and/or polymeric agent, may adhere to the substrate by means of internal bonding which causes the deposit's constituent molecules to interlock on the substrate (thereby holding such molecules in the proximity of the substrate and providing a self-sustaining coating that restrains the polymeric agent from departing the substrate), or may accomplish that end by some other mechanism or some combination of two or more of the foregoing. However, regardless of the mechanism by which the binding substance holds the polymeric agent on the inorganic material substrate, this development--while better than the technology discussed in the preceding paragraph--still could be improved to provide even longer-term durability of the polymeric agent on the substrate.
It would be a substantial advance to provide a composite demonstrating ultra long-term durability against the action of an aqueous medium, which composite contains a functionality capable of interacting with a species of interest extraneous to the composite, normally found in substances which are at least partly soluble in an aqueous medium.